Electrodes containing supported metal catalyst particles are used in electrochemical cells, such as fuel cells. For example, in a conventional hydrogen fuel cell, a supported platinum catalyst is used to oxidize hydrogen gas into protons and electrons at the anode of the fuel cell. At the cathode of the fuel cell, another supported platinum catalyst triggers an oxygen reduction reaction (ORR), leading to the formation of water.
The catalyst support is typically a conductive high surface area carbon. The catalyst support provides a surface over which the catalyst particles are dispersed and stabilized. However, the carbon support may have poor interactions with the catalyst particles, which results in changes in the properties of the electrode. More specifically, poor catalyst-support interactions results in particle size growth of the catalyst particles under dissolution/redeposition processes. The increase in size of the catalyst particles through dissolution/redeposition causes a loss in fuel cell performance. The poor interactions between the carbon and the catalyst particles can even result in irreversible loss of the catalyst in the cathode.
Additionally, carbon catalyst supports in fuel cells are susceptible to corrosion that results in carbon oxidation and, as a final stage, collapse of the carbon pore structure. Causes of corrosion include the presence of oxygen, water, and high electrode potential, especially on the cathode side. Corrosion also causes microstructural derogation and surface chemistry changes, which can result in an irreversible loss in catalyst performance, cross-over and ultimately in the complete failure of the fuel cell. An improved catalyst support is needed so that the performance of an electrochemical cell can be maintained.